Aqueous ink composition and colorants useful therein

ABSTRACT

As aqueous ink composition is provided having up to 5 wt. % of a colorant of the formula: 
     
         A--{Y--X--C(O)--R.sub.1 --C(O)O.sup.- }.sub.p 
    
     where A is an organic chromophore; Y is a polyoxyalkylene substituent; X is a radical of a reactive hydroxy, amino or thio group; and R 1  is C 2-30 , substituted or unsubstituted alkylene, alkenylene, or phenylenealkylene. A counter ion selected from alkaline metal ions, alkaline earth metal ions, ammonium ions, amine salts, and zinc ammonium complexes is present in approximately stoichiometric proportion or greater relative to the colorant in the ink composition.

This is a divisional application of U.S. patent application Ser. No.07/806,926 filed Dec. 11, 1991, now U.S. Pat. No. 5,176,745, for AQUEOUSINK COMPOSITION AND COLORANTS USEFUL THEREIN. Specific reference isbeing made herein to obtain the benefit of its earlier filing data.

BACKGROUND OF THE INVENTION

This invention relates generally to an aqueous ink compositioncontaining a colorant which is soluble as a salt, but is relativelywater insoluble in its acid form. In particular, the colorant is apolyoxyalkylene substituted organic chromophore which has been reactedwith a cyclic acid anhydride, dicarboxylic acid or derivative thereof,to provide a pendant carboxyl group.

Polyoxyalkylene substituted organic chromophores are well known in theart as exemplified by Brendle, U.S. Pat. No. 4,167,510 (fugitive tints),Baumgartner et al, U.S. Pat. No. 4,732,570 (colorants for thermoplasticresins) and Cross et al., U.S. Pat. No. 4,284,729 (colorants reactiveinto polyurethane resins). Additionally, fugitive colorants within theaforementioned class have been employed in children's marking pens dueto their water solubility, which allows for easy removal of the colorantfrom skin, clothes, painted surfaces, etc. In many ink applications,however, it is essential that the colorant in the ink composition remainpermanently affixed to the substrate to which it is applied.

The water solubility of dyestuffs may also be enhanced by grafting suchdyestuffs to a water soluble polymer backbone as disclosed in Hugl etal., U.S. Pat. No. 5,030,697. Suitable polymer backbones includeco-polymers of a acrylamide with unsaturated dicarboxylic acidanhydrides. Hugl et al. also provide a DNA or antigen reactive groupgrafted on to the polymer for linking the polymer bound dye to abiologically active material.

The gravure and flexographic printing industries are important areas ofink application requiring a high degree of integrity and permanence ofprinted images. Typical processes are based upon compositions containinga volatile organic solvent, such as toluene, a resin binder and apigment or dye to impart color. After the ink composition is applied toa substrate, the solvent is evaporated or absorbed, and the pigment ordye is affixed to the substrate by the binder. Concerns for theenvironment and limiting worker exposure to organic solvents haveincreased pressure on the printing industry to develop aqueous based inkcompositions. Despite the availability of a number of water soluble dyesand other colorants, such colorants remain essentially water solubleafter application and, therefore, lack the permanence found in organicsolvent based ink compositions.

SUMMARY OF THE INVENTION

Therefore, one of the objects of this invention is to provide an aqueousink composition.

Another object of this invention is to provide an aqueous inkcomposition having a colorant which is soluble therein.

Still another object of this invention is to provide a colorant which,after the ink has dried on a suitable substrate, is substantially lesswater soluble.

Accordingly, an aqueous ink solution is provided having a colorantcharacterized by a polyoxyalkylene substituted, organic chromophorewherein the polyoxyalkylene substituent is covalently bonded to acarboxylic acid. Preferably, a pendant or terminal hydroxy, amino orthio group of the polyoxyalkylene substituent is bonded through an acylgroup of the carboxylic acid, provided that the resultant colorant hasat least one carboxylic acid functionality. The colorant is soluble inwater as a salt and relatively insoluble in its acid form. Therefore, acounter ion selected from alkali metal ions, alkaline earth metal ions,zinc ammonium complexes, ammonium ions and amine salts, is provided inthe ink solution in approximately stoichiometric proportion or greaterrelative to said colorant. Particularly useful counter ions are ammoniumions which may optionally be substituted with from one to three groupsselected from C₁₋₁₈ alkyl, C₂₋₁₈ hydroxyalkyl, preferably C₁₋₄ alkyl andC₂₋₄ hydroxy alkyl, phenyl and alkylphenyl wherein the alkyl portion isC₁₋₄, such as amine salts of ethanolamine, diethanolamine andtriethanolamine, and amine salts of morpholine. Counter ions which arevolatile, comprise a volatile component or which migrate away from thecolorant after the ink solution is applied to a substrate are preferred.

The solubility of the colorant is further influenced by the number andtype of alkylene oxide radicals comprising the polyoxyalkylenesubstituent and the contribution of the carboxylic acid. Thus therelative water solubility or insolubility of the colorant in the form ofa salt or acid can be adjusted by altering the constituency of thepolyoxyalkylene substituent and the carboxylic acid.

DESCRIPTION OF THE PREFERRED EMBODIMENT OF THE INVENTION

Without limiting the scope of the invention, the preferred features ofthe invention are hereinafter set forth.

The ink compositions of the present invention are aqueous solutions ofone or more colorants. The colorants themselves are characterized bythree primary components: (1) an organic chromophore having (2) apolyoxyalkylene substituent and (3) a carboxylic acid covalently bondedto the polyoxyalkylene substituent. The colorant is soluble in theaqueous ink solution when the colorant is in the form of a salt.

A wide variety of polyoxyalkylene substituted organic chromophores andtheir preparation are well known in the art. These materials can berepresented by the general formula:

    A--{Y}.sub.p

where A is an organic chromophore, Y is a straight or branchedpolyoxyalkylene substituent comprised of from 1-200 radicals of C₂₋₁₈alkylene oxides. The chromophore is covalently bonded to thepolyoxyalkylene substituent by a linking group such as N, NR₃, O, S,SO₂, SO₂ N, SO₂ NR₃, CO₂, CON or CONR₃, where R₃ is H, C₁ -C₁₂ alkyl,phenyl or benzyl. Preferably, the linking group is N, NR₃, O, SO₂ N orSO₂ N or SO₂ NR₃. Two polyoxyalkylene substituents may be bonded to thechromophore through a trivalent linking group. The letter "p" representsthe number of polyoxyalkylene chains per chromophore and may be from1-6, preferably 1-4.

In a preferred embodiment, the polyoxyalkylene substituents areprimarily comprised of from 3 to 50 radials of ethylene oxide, propyleneoxide or random and block copolymers thereof. Minor amounts of glycidol,butylene oxide and other compatible monomers may also be present.

A wide variety of organic chromophores are suitable for use in thepresent invention. Examples of useful chromophores include: nitroso,nitro, azo, diarylmethane, triarylmethane, xanthene, acridine,quinoline, methine, thiazole, indamine, indophenol, lactone,aminoketone, hydroxyketone, stilbene, azine, oxazine, thiazine,anthraquinone, phthalocyanine or indigoid chromophore groups. Ofparticular interest are azo, methine, triphenylmethanes andanthraquinone chromophores. While metal containing chromophores, such asphthalocyanines, may also be employed, from an environmentalperspective, their use is less desirable.

Synthesis of organic chromophores containing polyoxyalkylenesubstituents are disclosed in Kuhn, U.S. Pat. No. 3,157,633, Brendle,U.S. Pat. No. 4,167,510, Cross et al., U.S. Pat. No. 4,284,729 andBaumgartner et al., U.S. Pat. No. 4,732,570, incorporated by referenceherein.

The polyoxyalkylene substituted organic chromophore is reacted with acarboxylic acid or derivative thereof to create a covalent bond.Preferably, the polyoxylakylene substituent has a pendant or terminalnucleophilic functionality selected OH, NH₂, NHR₂ and SH, wherein R₂ isC₁₋₁₈ alkyl, preferably C₁₋₈ alkyl, which reacts to create the bond. Ina more preferred embodiment, the nucleophilic functionality is OH or NH₂which is attached to a primary carbon.

The carboxylic acid may be incorporated into the colorant in a number ofways. In one embodiment, a cyclic acid anhydride is reacted with thenucleophilic functionality of the polyoxyalkylene substituent to providean ester, amide or thio ester bond and a pendant carboxyl group.Suitable cyclic acid anhydrides or equivalent derivatives includesuccinic anhydride, maleic anhydride, phthalic anhydride, trimelliticanhydride and dimethyl succinate. In a preferred embodiment, theoleophilic character of the colorant is increased by providing ananhydride with a substituent having up to 30 carbon atoms. By way ofexample, the substituent may be C₁ -C₃₀ alkyl, cycloalkyl or alkenyl,phenyl, naphthyl or benzyl. Particular useful anhydrides include:alkenyl succinic anhydrides such as octenyl succinic anhydride (OSA),dodecenyl succinic anhydride (DDSA) and octadecenyl succinic anhydride(ODSA); itaconic anhydride, citraconic anhydride, succinic anhydridesbonded to rosins and maleated rosins such as "Unirez" available fromUnion Carbide.

Alternatively, a polycarboxylic acid derivative such as a diacyl halidemay be reacted with the nucleophilic functionality of thepolyoxyalkylene substituent to form an ester, amide or thio ester.Standard esterification techniques known in the art may be used followedby hydrolysis of the unreacted acyl halide to form a carboxylic acidfunctionality.

A further embodiment of the invention may be realized by the reaction ofa polycarboxylic acid, such as malonic acid, adipic acid and sebacicacid, with the nucleophilic functionality of the polyoxyalkylenesubstituent to create an ester, amide or thio ester.

The above mentioned cyclic acid anhydrides, acyl halides anddicarboxylic acids may be substituted with CN, NO₂, halogens, and SO₃without deviating from the scope of the invention.

The colorant may be broadly represented by the formula:

    A--{Y--X--C(O)--R.sub.1 --C(O)OH}.sub.p

where A is an organic chromophore; Y is a polyoxyalkylene substituenthaving from 1 to 200 alkylene oxide radicals of C₂₋₁₈ alkylene oxides; Xis a nucleophile selected from O, NR₂ and S, where R₂ is H or C₁₋₁₈alkyl; R₁ is selected from alkylene, alkenylene, phenylene (exemplifiedby ethylene, vinylene and o-phenylene, respectively) andphenylenealkylene, any of which may optionally be substituted withalkyl, alkenyl or aryl, provided that the total number of carbon atomsis from 2 to 30; and p is an integer from 1 to 6.

An aqueous ink composition incorporating from 0.1 to 50 wt. % of thecolorant, preferably from 0.5 to 25 wt. %, may be provided by includinga counter ion in approximately stoichiometric proportion to saidcolorant. The counter ion may be provided in stoichiometric excess. Thecounter ion converts the colorant to its soluble salt form. As usedherein, the colorant is considered to be soluble if it has a solubilityin water of at least 1000 ppm. Suitable counter ions include alkalimetal ions, alkaline earth metal ions, zinc ammonium complexes such asZinplex 15 marketed by Ultra Additives, Inc., Patternson, N.J., ammoniumions and amine salts such as salts of morpholine. Especially useful areammonium ions which may optionally be substituted with from one to threegroups selected from C₁₋₁₈ alkyl, C₂₋₁₈ hydroxyalkyl, phenyl andalkylphenyl wherein the alkyl portion is C₁₋₄, such as amine salts ofethanolamine, diethanolamine and triethanolamine.

The ink solution may be advantageously applied to any number ofsubstrates including, by way of example, all types of paper, plastic,polymer films and synthetic fibers. In catalog printing operations, theink solution is applied to paper and dried at temperatures up to 212° F.Counter ions which are fugitive, either because they are volatile orcontain volatile components, or because they tend to migrate away fromthe colorant upon drying are preferred. For reference herein, counterions having boiling points less than 335° C. are considered volatile.

The aqueous ink composition may also include organic co-solvents such asC₁₋₈ alcohols, glycol ethyl ether (Cellosolve®) and acetates, withoutdeviating from the scope of the invention.

The invention may be further understood by reference to the followingexamples, but the invention is not intended to be unduly limitedthereby. Unless otherwise stated, all parts and percentages are byweight. The abbreviations "EO" and "PO" represent the residues ofethylene oxide and propylene oxide, respectively.

EXAMPLE ONE

A mixture of 16.5 parts of the thiophene based azo colorant described inExample 3 of U.S. Pat. No. 4,507,407, (CV=23.5), 24.0 parts of a bluepolymeric triphenylmethane colorant consisting of 4.3 wt. % ethyleneoxide polymer and 73.4 wt. % propylene oxide polymer, (CV=49.0), 56.2parts of a diaryl azo orange colorant containing 28 wt. % ethylene oxidepolymer and 46.2 wt. % propylene oxide polymer, (CV=24.1) and 3.3 partsof a methine yellow colorant containing 22.1 wt. % ethylene oxidepolymer and 62.4 wt. % propylene oxide polymer, (CV=29.4) were blendedwith good agitation and warming (40°-50° C.) to prepare a blackcolorant. To this blend were added 51.3 parts octenylsuccinic anhydrideand the reaction mixture heated to 90° C. for 3h under a nitrogenblanket.

An aqueous ink concentrate was prepared from this reaction mixture byadding 45.4 parts of the colored, octenylsuccinic acid derivative slowlyand with good agitation and at room temperature to 8.6 parts 30%ammonium hydroxide previously diluted with 146 parts deionized water.This ink concentrate was then used to prepare inks having concentrationsof 0-15% by dilution with deionized water.

EXAMPLE TWO

A reaction mixture of the benzothiazole based azo red colorant describedby Cross in U.S. Pat. No. 4,284,729, (100 parts) and octenylsuccinicanhydride (62.6 parts; 1.1 equivalents/hydroxyl group) was heated at 90°C. for 3h under nitrogen atmosphere to form an ester between theanhydride and polymeric colorant.

An aqueous ink concentrate was prepared from the above reaction mixtureby adding 48.4 g of the mixture to a solution of 2.8 g 30% ammoniumhydroxide and 141.4 g deionized water to give an ink concentrate ofcolor strength CV=9.5.

EXAMPLE THREE

The colorant blend described in EXAMPLE ONE, 100 g, and 26.5 g ofphthalic anhydride (1.1 eq./hydroxyl group), was heated to 90° C. for 3hwith good agitation and nitrogen atmosphere to give the phthalic esterderivatives of the colorant blend.

An aqueous ink concentrate was prepared by adding 38 g of the colorantto a solution of 6.3 g 30% ammonium hydroxide and 155.7 g deionizedwater.

EXAMPLE FOUR

A mixture of 75.1 parts of the polymeric methine yellow colorantdescribed in EXAMPLE ONE, and 24.9 parts octenylsuccinic anhydride (1.1eq/hydroxyl group) were heated under an inert atmosphere and with goodagitation at 110° C. for 3 hours. 4.0 g of this colorant (CV=24.3) wasadded to a solution consisting of 0.5 g 30% ammonium hydroxide in 22.2 gdeionized water to give a 15% solids inks concentrate. This inkconcentrate was further reduced with water to form a 7.5% solutionsuitable for ink jet printing.

The following test was performed to determine the stability of the driedink on paper:

Approximately 1-2 grams of the aqueous ink composition of Example 4 wasused to make a printed image using a K-proofer printability tester. Theimage was allowed to dry at room temperature for 10-15 minutes. Thedried image was placed into water and showed no bleed of color.

EXAMPLE FIVE

A mixture of a polymeric diaryl azo orange colorant containing 52.2 wt.% of ethylene oxide polymer, 98 parts, and 171 parts octenylsuccinicanhydride (1.2 eq/hydroxyl group) were combined with strong agitationunder an inert atmosphere and the reaction mixture heated to 90° C. for3h. A 15% aqueous ink concentrate based on color content was preparedfrom 22.5 g of the OSA modified colorant added to a solution of 7.2 g30% ammonium hydroxide in 120.3 g deionized water. This concentratecould be diluted further with water to give suitably performing ink jetinks.

EXAMPLE SIX

A mixture of an analog of the polymeric blue colorant described inEXAMPLE ONE but having a polymeric contribution of 51.7 wt. % polymericethylene oxide exclusively, 116 g, was heated under an inert atmosphereand with good agitation with 151 g octenylsuccinic anhydride (1.2eq/hydroxyl group) to give the tetraester-tetracarboxy-blue. An aqueousink concentrate was prepared containing 15% of the color by adding 22.5g of the colorant an ammoniacal solution prepared by diluting 6.5 gammonium hydroxide with 121 g deionized water.

EXAMPLE SEVEN

The blue polyoxyethylene containing colorant used in EXAMPLE SIX, 77.5 gwas reacted with 48 g succinic anhydride (1.2 eq/hydroxyl group) at 115°C. for 2.5h. Similarly, the orange chromogen of EXAMPLE FIVE, 57.4 g,was reacted with 48 g succinic anhydride (1.2 wq/hydroxy group) to givethe tetraester-tetracarboxy derivative. Each of these was independentlydiluted with ammoniacal water (7.2 g 30% ammonium hydroxide in 120.3 gdeionized water) to give a 15% solution by adding the colorant slowlyand with good agitation to the aqueous diluent.

These 15% ink concentrates could be further reduced with water to adesired color strength suitable for ink jet printing.

EXAMPLE EIGHT

75 parts of the methine yellow colorant of Example 1 was taken with 25parts of octenylsuccinic anhydride and heated under nitrogen at 95° C.for 3 hours. The resultant colorant (adduct) had a color value of 24.5.

The adduct was taken in a 500 ml. beaker and its Ph adjusted to 8.5 withcaustic. Zinplex 15, a zinc crosslinking/complexing agent was slowlyadded with good agitation. A total of 21 parts of Zinplex 15 were added,which was estimated to provide 30% crosslinking of the polymer.

Next, 0.75 parts of the adduct and Zinplex composition was mixed with10.5 parts of rosin based varnish to make an ink which, when drawn onpaper, gave an image that is completely water resistant.

Additionally, 0.75 parts of the adduct and Zinplex composition was mixedwith 10.5 parts of an acrylate emulsion resin to make an ink. The inkwas drawn on paper, and the resulting image was completely waterresistant.

EXAMPLE NINE

200 parts of the methine yellow colorant of Example 1 was placed in a3-neck round bottom flask equipped with a mechanical stirrer and anitrogen inlet. Next, 55 parts (2 moles) of trimellitic anhydride and0.5 parts of N-methyl imidazole were added and the mixture was heated to90° C. for 5 hours. The reaction was monitored by IR for disappearanceof an anhydride peak at 1830 cm⁻¹. The product had a color value of 25.7and was very viscous.

10 parts of 38% NaOH was added to 50 parts of the above product and themixture was monitored for an exotherm. The resulting compound wascompletely water soluble. Finally, water was stripped off the product to0.5% moisture. One part of the sodium salt of the acid was taken with 21parts of a rosin-based varnish in toluene to make an ink. The ink wasused to make a printed image with a K-proofer printability tester.Putting the image under tap water and holding it for one minute showedno discernable transfer of color to any other part of the paper or therinse water.

In another experiment, 0.5 parts of the sodium salt was added to 10.5parts of a Joncryl 87 acrylate resin and 0.5 parts of water. Thedraw-down image was water resistant. Holding the paper under tap waterfor one minute resulted in no apparent migration to another part of thepaper or to the rinse water.

EXAMPLE TEN

150 parts of p-formyl-N,N-bis(hydroxyalkylpolyoxyalkylene) aniline wastaken in a 3-neck round-bottom flask with 297 parts of a rosin basedUNIREZ adduct (the adduct before zinc or calcium salt formation of theacid groups) and 1 part of magnesium oxide. The reaction mixture washeated to 240° C. under nitrogen for 24 hours. The reaction was followedby acid number calculation.

To the above product was added 24 parts of ethyl cyanoacetate and 3.5parts of ammonium carbonate. The reaction mixture was heated for 3 hoursunder nitrogen, whereupon a yellow colorant was obtained.

To 1.5 parts of this colorant, 10.5 parts of rosin based varnish wasadded and the mixture used as an ink for a draw-down on paper. The finalimage was totally water resistant.

There are, of course, many alternate embodiments and modifications whichare intended to be included within the scope of the following claims.

What we claim is:
 1. A colorant comprising a compound of the formula:

    A--{Y--X--C(O)--R.sub.1 --C(O)OH}.sub.p

where A is an organic chromophore; Y is a polyoxyalkylene substituenthaving from 1 to 200 alkylene oxide radicals of C₂₋₁₈ alkylene oxides; Xis a nucleophile selected from O, NR₂ and S, where R₂ is H or C₁₋₁₈alkyl; R₁ is selected from alkylene, alkenylene, phenylene andphenylenealkylene, which may optionally be substituted with alkyl oralkenyl, provided that the total number of carbon atoms is between 2 and30; and p is an integer from 1 to
 6. 2. The colorant of claim 1 whereinA is selected from nitroso, nitro, azo, diarylmethane, triarylmethane,xanthene, acridine, quinoline, methine, thiazole, indamine, indophenol,lactone, aminoketone, hydroxyketone, stilbene, azine, oxazine, thiazine,anthraquinone, phthalocyanine or indigoid chromophore groups.
 3. Thecolorant of claim 2 wherein Y comprises from a total of from 3 to 50 ofsaid alkylene oxide radicals and said alkylene oxides are selected fromethylene oxide and propylene oxide.
 4. The colorant of claim 3 wherein Xis O or NR₂ and R₂ is C₁₋₈ alkyl.
 5. The colorant of claim 4 wherein R₁is selected from ethylene, vinylene and phenylene, any of which mayoptionally be alkyl or alkenyl substituted.
 6. The colorant of claim 3wherein R₁ is selected from ethylene, vinylene and o-phenylene, any ofwhich may optionally be alkyl or alkenyl substituted.
 7. The colorant ofclaim 1 wherein R₁ is selected from ethylene, vinylene and phenylene,any of which may optionally be alkyl or alkenyl substituted.
 8. Thecolorant of claim 7 wherein A is selected from azo, methine,triphenylmethane and anthraquinone chromophores and p is 1 to
 4. 9. Thecolorant of claim 8 wherein Y comprises from a total of from 3 to 50 ofsaid alkylene oxide radicals and said alkylene oxides are selected fromethylene oxide and propylene oxide.
 10. The colorant of claim 9 whereinX is a primary or secondary O or NR₂ and R₂ is C₁₋₈ alkyl.
 11. Thecolorant of claim 9 wherein X is a primary O.
 12. The colorant of claim5 wherein --C(O)--R₁ --C(O)OH is the residue of a cyclic acid anhydrideselected from the group consisting of octenyl succinic anhydride,dodecenyl succinic anhydride and octadecenyl succinic anhydride, whichhas been reacted with said nucleophile.
 13. The colorant of claim 7wherein --C(O)--R₁ --C(O)OH is the residue of a cyclic acid anhydrideselected from the group consisting of octenyl succinic anhydride,dodecenyl succinic anhydride and octadecenyl succinic anhydride, whichhas been reacted with said nucleophile.
 14. The colorant of claim 10wherein --C(O)--R₁ --C(O)OH is the residue of a cyclic acid anhydrideselected from the group consisting of octenyl succinic anhydride,dodecenyl succinic anhydride and octadecenyl succinic anhydride, whichhas been reacted with said nucleophile.
 15. The colorant of claim 11wherein --C(O)--R₁ --C(O)OH is the residue of a cyclic acid anhydrideselected from the group consisting of octenyl succinic anhydride,dodecenyl succinic anhydride and octadecenyl succinic anhydride, whichhas been reacted with said nucleophile.
 16. A colorant comprising anorganic chromophore, having a poly(oxyalkylene) substituent of from 1 to200 radicals of alkylene oxide radicals of C₂₋₁₈ alkylene oxides, saidpoly(oxyalkylene) substituent having a pendant or terminal groupselected from OH and NH₂ and NHR₂ wherein R₂ is C₁₋₁₈ alkyl, which formsan ester or amide linkage respectively with an acyl group of a residueof a cyclic acid anhydride, said residue of a cyclic acid anhydridehaving a pendant carboxyl group.
 17. The colorant of claim 16 whereinsaid organic chromophore is selected from nitroso, nitro, azo,diarylmethane, triarylmethane, xanthene, acridine, quinoline, methine,thiazole, indamine, indophenol, lactone, aminoketone, hydroxyketone,stilbene, azine, oxazine, thiazine, anthrquinone, phthalocyanine orindigoid chromophore groups.
 18. The colorant of claim 17 wherein saidpoly(oxyalkylene) substituent comprises from a total of from 3 to 50 ofsaid alkylene oxide radicals and said alkylene oxides are selected fromethylene oxide and propylene oxide and wherein said residue of a cyclicacid anhydride is a derivative of succinic anhydride, maleic anhydride,phthalic anhydride or trimellitic anhydride, any of which may besubstituted with alkyl or alkenyl, provided that the total number ofcarbon atoms is between 4 and
 32. 19. The colorant of claim 18 whereinsaid cyclic acid anhydride is octenyl, dodecenyl or octadecenyl succinicanhydride.
 20. The colorant of claim 19 wherein said pendant or terminalgroup of said polyoxyalkylene substituent is OH.